abstract
The thermal behavior of the hydrophobic eutectic mixtures formed by l-menthol (MEN) with 4-methoxyphenol (4-Met), 2-tert-butyl-4-methoxyphenol (BHA), 2-tert-butyl-4-ethylphenol (TBEP), and tert-butylhydroquinone (TBHQ) has been investigated to elucidate the different factors governing the solid-liquid equilibrium (SLE) at the molecular level. Our comparative study highlights the contribution of hydrogen-bonding (H-bonding) asymmetry of deep eutectic solvent (DES) precursors, i.e., their ability to act as strong H-bond donors and weak H-bond acceptors or vice versa. When deriving from resonance effects, this concept was previously presented as "polarity asymmetry" and introduced to explain the thermal behavior of type V DES. Here, we expand this concept to demonstrate that steric factors led by the insertion of ad hoc functional groups in the precursor molecules also have a dominant role in the deviation from thermodynamic ideality. In this way, an increasing temperature depression is observed starting from the 4-Met/MEN mixtures up to the BHA/MEN, TBHQ/MEN, and TBEP/MEN ones. The SLE prediction has been carried out through an innovative approach combining the COSMO-RS solvation model and density functional tight-binding molecular dynamics simulations, benchmarked against experimental data, and presented here for the first time. The impact of this work is that of providing new tools for a more conscious understanding and design of hydrophobic type V DES as new sustainable media for applicative purposes.
keywords
ZETA VALENCE QUALITY; PARTICLE MESH EWALD; BASIS-SETS; COSMO-RS; DENSITY; MIXTURES; ELECTRODEPOSITION; PARAMETRIZATION; APPROXIMATION; REFINEMENT
subject category
Chemistry; Science & Technology - Other Topics; Engineering
authors
Mannucci, G; Teixeira, G; Sosa, FHB; Palluzzi, M; Busato, M; Coutinho, JAP; D'Angelo, P
our authors
Filipe Hobi Bordon Sosa
Junior Researcher
Gabriel Teixeira Santos
PhD Student
Projects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
The authors acknowledge the European Union-NextGenerationEU under the Italian Ministry of University and Research (MUR), Network 4 Energy Sustainable Transition-NEST project (MIUR project code PE000021, Concession Degree no. 1561 of October 11, 2022)-CUP C93C22005230007. This work was partially developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). G.T. thanks FCT for his Ph.D. grant (UI/BD/151114/2021). F.H.B.S. acknowledges FCT-Fundacao para a Ciencia e a Tecnologia, I.P. for the researcher contract CEECIND/07209/2022, under the Scientific Employment Stimulus-Individual Call.